1. Field of the invention
The present invention concerns a method of increasing the anti-wettability of a body--i.e. of making it more hydrophobic vis a vis a fluid.
The invention is also directed to the bodies obtained after treatment by the method of the invention.
These bodies can be porous bodies treated directly by a plasma process or bodies obtained by sintering balls treated by a plasma process.
2. Description of the prior art
It is desirable to increase the wettability of a porous body vis a vis a fluid in many applications.
One of these applications concerns the writing tips of markers. French patent application n.degree. 96 01 700 of Feb. 12, 1996 describes a method of increasing the wettability of a porous body such as the writing tip of a marker vis a vis the ink. This method consists in subjecting the porous body to a post-discharge nitrogen plasma.
In contrast, the present invention is directed to increasing the anti-wettability of a porous body, i.e. to reducing its ability to absorb a fluid.
European patents 0 516 538 and 0 681 924 describe a marker having a body enclosing an ink reservoir and a tip having one end in contact with the ink and surrounded by a porous polymer material sleeve.
The Applicant has found that the marker works better if the anti-wettability of the aforementioned porous sleeve vis a vis the ink is increased.
The invention is specifically directed to achieving this particular objective, without limiting its application to the above example.